Nady, a 33-year-old who has spent time with six major league teams, has reported to minor league camp and will start the season at Triple-A Syracuse. It's a straight minor league deal and has no outs.
"He's a player I've always had interest in," Rizzo said. "He's coming off a few injury-plagued seasons. He's motivated and he's coming into camp in great shape. He'll be on the minor league side getting his swings in, trying to get back into baseball shape, and we'll take it from there.
"He's been an accomplished major league player in the past. He's a versatile guy that can play several positions. He's a terrific guy to have in the clubhouse, a good presence, a major league veteran and a guy that can swing the bat from the right side and play the four corner positions."
With Michael Morse and Adam LaRoche battling lingering injuries, Nady's signing provides insurance both at first base as well as the corner outfield spots.
Nady hit 25 home runs and had 97 RBIs in 2008, spending the early part of the season with the Pirates before being traded to the Yankees. But Nady had to undergo Tommy John surgery the next season and only appeared in seven games with the Yankees in 2009.
He played in 119 games with the Cubs in 2010, hitting .256 with six homers and 33 RBIs, and hit .248 last season in 223 at-bats with the Diamondbacks but suffered a fractured left hand when he was hit by a pitch in August.
The Nats watched Nady work out in California this last week, and liked the way he looked.
"It looked like he's swinging the bat and in good shape," Rizzo said. "He's knocking off some rust right now, but we feel that coming into minor league camp, it's a very low-risk, no-risk acquisition if you will, and a guy that could reap us some benefits down the road."